Effect Of Several Organic Fertilizer Materials On Soil Biochemistry Properties And Crop Growth

Because of the plant physiological activity and the ability of compounding plant physiological regulatory precursor with microbial action, organic fertilizer materials have been widely applied to various types of soil and crop. Effects of organic fertilizer materials on soil ecological environment, crop growth, quality and human health have gradually aroused people’s attention. In this paper, lab simulated experiment and solution culture experiment were conducted to study the effects of organic fertilizer materials such as chitin(CI), weathered coal(WC), seaweeds(SW), humic acid sodium(HANa), nitrohumic acid(NA), papermaking black liquor(PB) on soil enzyme activity, soil microbial numbers, soil heavy metal adsorption, maize germination rate, pakchoi growth and quality. The systematic effects and the mechanism of organic fertilizer materials on soil ecological environment and crop growth were discussed. It provides theoretical reference for the scientific and reasonable application of organic fertilizer materials. The main results were as followed:1. The activities of soil urease, catalase, sucrase and neutral phosphatase were all significantly increased by the application of chitin. The activity of urease was decreased and the other three enzymes were increased by the humic acid sodium, and both of their effects were proportional with the application amount. The black liquor both showed significantly decreasing effects on the urease and neutral phosphatase activities, but no significant effects on sucrase activity, the high amount showed significantly decreased effects on the soil catalase activity.2. All of the organic fertilizer materials significantly increased the SMBC and SMBN after25d. They were respectively increased of60.42%and103.55%by the application of humic acid sodium,39.10%and88.41%by the chitin,15.94%and43.43%by the black liquor. The chitin increased the actinomycetic number while decreased the fungal number significantly. The humic acid sodium increased the number of bacteria and actinomycetes while decreased the fungal number significantly, and their effects were both proportional to the concentration. The black liquor had significant promoting effects on the fungal number but inhibitory effects on the actinomycetic number, and showed significant inhibitory effects only in the early period (5d-25d).3. Isothermal adsorption curve of copper and zinc absorbed by different organic fertilizer materials can match with Langmuir and Freundlich equation well, and the Freundlich was better. Cu2+and Zn2+adsorption of each materials increased with the equilibrium concentration, the increase amplitude is larger in low concentration while smaller in high concentration. As for the Cu2+absorption, the adsorption capacity and intensity of Cu2+were both enhanced by the weathered coal, humic acid sodium and amino acid, the adsorption intensity was enhanced by the black liquor and the adsorption capacity was enhanced by the chitin. As for the Zn2+absorption, the capacity and intensity were both enhanced by the amino acid and humic acid, the intensity was enhanced by the weathered coal and seaweeds.4. Effects of amino acid on the corn germination rate were increased by8.58%, but no significant differences. Both of the chitin and seaweeds had double adjustment effects, promotion to the low concentration while inhibition to the high concentration. The respective optimal concentration was20mg·L-1and40mg·L-1, and respectively increased11.08%and9.21%. The high amount of black liquor had inhibition effects on the grem of corn.5. The organic fertilizer materials showed significant increase on the height, leaves, maximum leaf area, root length, root area, chlorophyll and carotenoid content of hydroponic pakchoi, significantly promoted the vegetative growth of pakchoi and laid foundation for the production. On the fresh weight of single plant, humic acid sodium, amino acid and chitin respectively increased39.37%,29.77%and27.28%, while the dry weight increased39.39%,29.55%and27.27%respectively. The chitin and humic acid sodium showed significant increase on the contents of NO3-N, but did not over the food safely standard, the amino acid decreased of2.62%while did not reach a significant difference, but it had a beneficial effect to keep the quality of pakchoi.